Process for finishing textiles and the product produced



Patented Jan, 1, 1946 PROCESS FOR FINISHING TEXTILES AND THE PRODUCTPRODUCED James Andrew Clark, Port Chester, N. Y., assignor to SylvaniaIndustrial Corporation, Fredericksburg, Va., a corporation oi. VirginiaNo Drawing. Application October 23, 1941, Serial No. 416,214

9 Claims. (01. ur1s3) This invention relates to a process for-finishingtextile materials, and more particularly relates to a process fortreating pile fabrics and the article so produced, and to correlatedimprovements designed to enhance the properties and to increase theutility of such products.

Heretofore, pile fabrics such as carpets, velvets, plush, mohairs,velours, and the like, have been coated on the back with rubber latex inorder to bind the pile arns to the ground yarns but this has been foundto be not entirely satisfactory as the rubber tends to become brittlewith age, and is not resistant to laundry fluids containing bleachingagents. Since normal rubber latex contains an average of from about 28%to 38% rubber solids, large quantities are necessary for an efiectivetreatment. As latex is a relatively expensive and unstable material itis desirable to decrease the quantity employed for this purpose. Otherattempts have been made to bind the pile yarns to the ground yarns withsolu-,

It is another object of the invention to provide a pile fabric in whichthe piles are permanently bound to the ground material in a mannerwhereby the pile yarns are secured against withdrawal.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

According to the present invention a pile fabric of any type is treated,preferably by back filling, with a composition comprising an alkalinedispersion of an alkali-soluble water-insoluble cellulose material andrubber latex media, the rubber solids and cellulose material areconjointly coagulated upon the fabric, thereby forming a continuouspermanent coating which binds the pile tufts and individual fibers tothe ground threads of the fabric. Various fillers, pigments, and thelike, may be added to the mixture before or during application of thecomposition to the fabric. The invention also relates to a pile fabrictreated in accordance with the foregoing process.

The expression "pile fabric" as used in the specification and claims isintended to include fabrics wherein the yarn shows an end, in contrastto a side. The pile may be warp pile, weft pile, knotted pile, looppile, or pile on pile, according to th method of weaving, tying,lashing, shearing or cutting. Pile fabrics which may be treated inaccordance with the invention comprise velvets, velveteens, plush,corduroy, velours, mohairs, terry, astrakhan and the like. Such pilefabrics may be used as rugs, carpeting, furniture upholstering,automobile lining and seat covering, wearing apparel and the like.

The invention accordingly comprises the several steps and relation ofone or more of such steps with respect to each of the others, and thearticle possessing the features, properties, and the relation ofelements, which are exemplified in the following detailed disclosure,and the scope of the invention will be indicated in the claims.

Cellulose ethers which may be employed in the invention comprise as aclass those cellulose ethers which are soluble in aqueous alkalisolutions but which are insoluble in water, such for example, as alkylcellulose ethers, hydroxy-alkyl cellulose ethers, carboxy-alkylcellulose ethers,

mixed ethers such as the alkyl, hydroxy-alkyl cellulose ethers, and thelike. The alkyl ethers of cellulose comprise methyl cellulose, ethylcellulose, propyl cellulose and the like. The bydroxy-alkyl. ethers ofcellulose comprise hydroxymethyl cellulose ethers, hydroxy-ethylcellulose ethers, as well as mixed alkyl, hydroxy-alkyl cellulose etherssuch as methyl hydroxy-ethyl cellulose, and the like. The carboxy-alkylcellulose ethers which may be employed comprise cellulose glycolic acidether and its homologues.

In addition to employing alkali-soluble cellulose ethers, there may beemployed alkali-soluble celluloses such as degraded alpha-cellulose,betacellulose and oxy-cellulose, which may be produced by degradation.and/or oxidation by heat, acids, alkali and the like, which treatmentsresult in a product which is soluble in alkali, such as 8%-10% causticsoda solution, upon cooling or freezing the solution. From suchsolutions the alkali-soluble cellulose may be precipitated by the samecoagulants which are used for precipitating the alkali-soluble celluloseethers.

The rubber latex employed may be crude rubber latex or concentrated orcreamed rubber latex depending upon the quality of the finish desired,to which there may be added the usual compounding ingredients assulphur, zinc oxide, ac-

I celerators, antioxidants, and the like, which are necessary forvulcanization of the latex; also suitable inert fillers, such, forexample, as talc,

wood flour, fullers earth, chalk, clay, and the like, to provideadditional weight. Various alkali-stable pigments, dyes and the like maybe employed for coloring the composition.

Preferably, in forming the coating composition for a pile fabric, acolloidal solution comprising from 1-12% alkali-soluble water-insolublecellulose material in from 2-16% aqueous solution of a fixed alkali, forexample sodium hydroxide or potassium hydroxide, is slowly mixed with arubber latex solution comprising 28-70% rubber solids. In a preferredembodiment there is employed an alkali solution of from 3-8% alkaliconcentration having dispersed therein from 3-8% alkali-solublewater-insoluble cellulose ether in which there is dispersed a latexsolution having from l-16% rubber content by weight. The ratio of rubbersolids to solid cellulose ether may be varied depending on the type offabric treated and the type of back finish desired. In general, thecellulose ether may be mixed with a solution of rubber latexin widelydiffering proportions, for example, in a ratio of 2 or 3 parts ofcellulose ether to 1 part rubber solids. In a preferred embodiment thereis employed a ratio of 1 part cellulose ether to 1 part of rubber solidsby weight. In many cases it may be desirable to employ a greater amountof rubber solids contained in the latex solution in proportion to theamount of cellulose ether employed, as, for example, 2 parts of rubbersolids to 1 rt of cellulose ether by weight.

For simultaneously coagulating the cellulose ether and the rubber theremay be used the known coagulants for cellulose ether and rubber latexsuch, for example, as an acid, acid gas and acid salt or a concentratedsalt solution which coagulates by salting out, or by heating thecomposition, or by evaporating the water by means of a stream of hotair.

By way of illustrating but not by way of limiting the invention, thefollowing examples are given. All percentages recited are based upon thedry weight of the materials used.

Example I A colloidal solution was prepared by dissolving 8 parts ofalkali-soluble water-insoluble hydroxyethyl cellulose in 92 parts of a4% sodium hydroxide solution. 'To 100 parts of the above solution therewere added 9.5 parts of a rubber latex containing 64% rubber solids. Thecomposition was then mixed thoroughly to provide an homogeneousdispersion and then applied to a pile fabric by back-filling. In thismanner the composition was pressed around the loops of the pile tuftswhich extended through the back of the fabric as well as around the warpand filling threads.

After back-filling, the treated fabric was passed into an aqueoussolution comprising 5% acetic acid which simultaneously coagulated thecellulose ether and the rubber. The fabric after pas- Example II A woolplush fabric, intended as an automobile body lining, was treated inmanner similar to that recited in Example I, employing 4 parts ofalkali-soluble water-insoluble hydroXy-ethyl cellulose dispersed in 96parts of a 4% aqueous caustic alkali solution to which there was added asufilcient amount of a 64% rubber latex to give an amount of rubberequivalent to the weight of the hydroxy-ethyl cellulose present. Thecoating composition was sprayed on the back of the plush fabric, and thesurplus composition was scraped off by means of a doctor blade whichcaused the composition to spread and form a continuous film on thefabric. The plush fabric was next passed through a coagulating bathcomprising approximately 10% sulfuric acid which simultaneouslycoagulated the rubber and the cellulose ether.

- The plush was found to have less rubbery feel and an increasedresistance to abrasion. This permitted finishing the plush inconventional manner and the finished material had improved appearanceand handle.

Various thickening agents may be employed to enhance the mechanicalapplication of the composition to the'pile fabric. .Such thickeners tendto increase the viscosity, and may comprise starch, casein, gelatin,water-soluble cellulose others but in general these are not needed sincethe alkali-soluble cellulose ether serves this purpose.

'Among the advantages of the coating composition is that there is formedan improved anchoring film for the pile. threads. Furthermore,

the alkali-soluble water-insoluble cellulose ether employed inapplicant's composition forms a surface coating for the individualrubber particles thus increasing their resistance to ageing. It has beenfound that applicant's composition is more stable than a latexcomposition used alone. This is probably due to the increase in alkalicontent employed to dissolve the cellulose ether, which fixed alkali hasa tendency to stabilize the composition, Both alkali-solublewater-insoluble cellulose ether and rubber in the form of latex arehydrophilic, but when the latex is coagulated to form a deposited rubberthe solid rubber is hydrophobic, the cellulose ether still remaininghydrophilic. Hence the film or coating formed from the presentether-latex composition is more water-repellent than is a film formedfrom the cellulose ether alone.

Further, it has been found that a satisfactory binding and finish isprovided for a pile fabric employing the present composition as comparedto the use 'of rubber latex alone, at the same time using considerablyless latex, thus resulting in a saving in cost and material. Whenemploying rubber latex alone the textile acquires the character of arubberized fabric, whereas the present composition results in a textilefinish which does not alter materially the textile appearance and handof the article.

In addition, the alkali-soluble water-insoluble cellulose ether employedis not subject to oxidation and therefore protects the rubber fromoxidation. The alkali-soluble cellulose ether employed in the presentcomposition enables one to plication.

vary the viscosity of the composition and thus make the process moreflexible in industrial ap- Since the viscosity of rubber latex alone isnot easily varied per se, the invention enables the composition to beused in a wider range of different fabrics and processes.

Since certain changes in carrying out the above process, and certainmodifications in the article which embody the invention may be madewithout departing from its scope, it is intended that all mattercontained in the above description shall be interpreted as illustrativeand not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed, and all statements of the scope of the invention which, as amatter of language, might be said to fall therebetween.

Having described my invention,'what I claim as new and desire to secureby Letters Patent is:

1. In a process for finishing a pile fabric, the steps comprisingback-filling said pile fabric with a composition comprising a dispersionin an aqueous solution of a fixed caustic alkali, an alkali-solublewater-insoluble cellulose hydroxyalkyl ether and rubber latex,conjointly coagulating. the rubber and the cellulose ether on thefabric, thereby forming a continuous permanent finish on the fabric.

2. In a process for finishing a pile fabric, the steps compriseback-filling said fabric with a composition comprising a dispersion inan aqueous solution of a fixed caustic alkali, an alkalisolublewater-insoluble hydroxy-ethyl cellulose ether and rubber latex, theamount of said cellulose ether being greater than the amount of rubher,in said dispersion, conjointly coagulating the rubber and the celluloseether upon the fabric, thereby forming a permanent deposit which bindsthe pile tufts to the fabric,

3. In a process for finishing a pile fabric, the steps comprisingpadding the back of said fabric with a composition comprising adispersion in an aqueous solution of a fixed caustic alkali, analkali-soluble water-insoluble cellulose ether containing hydroxy-allcvigroupsand rubber latex, passing said padded fabric into an acid whichconjointly coagulates the rubber and the cellulose ether on the fabric,thereby forming a continuous permanent finish on the back ot-the fabric.

4. In a process for finishing a pile fabric, the steps comprisingtreating the back of said fabric with a composition comprising adispersion in an aqueous solution of a fixed caustic alkali, an

alkali-soluble water-insoluble hydr xy-alkyl cellulose ether and rubberlatex, the amount of said cellulose ether being greater than the amountof rubber therein, conjointly coagulating the rubber and the celluloseether on the fabric, thereafter vulcanizing the rubber, thereby forminga continuous permanent coating forthe back of said pile fabric.

5. In a process for finishing a pile fabric, the steps comprisingtreating the back of said fabric with a composition comprisingadispersion in an aqueous solution of a fixed caustic alkali, analkali-soluble water-insoluble hydroxy-alkvl cellulose ether and aheat-sensitized rubber latex, heating the fabric to cqnjointly coagulatethe heat-sensitized latex and the cellulose ether on the fabric, therebyforming a continuous permanent finish on the fabric.

6. As an article of manufacture, a. pile fabric having a permanentdeposit on its back comprising a conjointly coagulated alkali-solublewaterinsoluble hydroxy-alkyl cellulose ether and rubber.

'7. As an article of manufacture,.a pile fabric back-filled on itsreverse side with a, composition comprising a conjointly coagulateddeposit consisting essentially of an amount of alkali-solublewater-insoluble hydroxy-alkyl cellulose ether and a smaller amount ofrubber, said cellulose ether and said rubber being intimately admixed.

8. An adhesive composition suitable for application to the back of pilefabrics, comprising an aqueous dispersion of an alkali-solublewater-insoluble cellulose ether, rubber latex, and a fixed causticalkali, the alkali serving to maintain the cellulose ether in solutionand also to stabilize the rubber latex against coagulation.

9. An adhesive composition suitable for application to the back of pilefabrics, comprising an aqueous dispersion of alkali-solublewater-insoluble cellulose ether, heat-sensitized rubber latex, avulcanizing accelerator for the rubber, a fixed caustic alkali, thealkali serving to main tain said cellulose ether in solution and tostabilize the rubber latex against coagulation.

JAMES CLARK.

